Data from: Moderation is best: effects of grazing intensity on plant-flower visitor networks in Mediterranean communities

The structure of pollination networks is an important indicator of
ecosystem stability and functioning. Livestock grazing is a frequent land
use practice that directly affects the abundance and diversity of flowers
and pollinators and, therefore, may indirectly affect the structure of
pollination networks. Here we studied how grazing intensity affected the
structure of plant-flower visitor networks along a wide range of grazing
intensities by sheep and goats, using data from 11 Mediterranean
plant-flower visitor communities from Lesvos Island, Greece. We
hypothesized that intermediate grazing might result in higher diversity as
predicted by the Intermediate Disturbance Hypothesis, which could in turn
confer more stability to the networks. Indeed, we found that networks at
intermediate grazing intensities were larger, more generalized, more
modular, and contained more diverse and even interactions. Despite general
responses at the network level, the number of interactions and
selectiveness of particular flower visitor and plant taxa in the networks
responded differently to grazing intensity, presumably as a consequence of
variation in the abundance of different taxa with grazing. Our results
highlight the benefit of maintaining moderate levels of livestock grazing
by sheep and goats to preserve the complexity and biodiversity of the rich
Mediterranean communities, which have a long history of grazing by these
domestic animals.